Diesel internal combustion engines can return fuel to a fuel tank. Returning fuel can have higher temperatures than fuel in or leaving the tank. In which case it can be desirable to cool fuel re-entering the fuel tank. Traditionally, this is done by using air fans, coolant or heat exchangers. Because these systems require additional parts, these systems can add unnecessary weight, expense and complexity to the fuel line assembly. Additionally, controls are typically needed to regulate these systems in order to avoid cooling or heating the fuel when doing so is not needed.
For example, U.S. Pat. No. 6,626,162 titled “Diesel Fuel Recycling System and Apparatus to Reduce Vapor Emissions of Diesel Fuel” discusses a recycling fuel delivery system that selectively routes fuel from a heat exchanger to the vehicle fuel tank or delivery line. This system, however, uses a heat exchanger incorporated with the vehicle heating, ventilation, and air conditioning system. Controls are used to regulate the heat exchanger; moreover, because the system is intertwined with the vehicle HVAC, HVAC performance can be compromised when fuel is being cooled.
Therefore it is desirable to have a lower cost and less complex system of supplying cooling on-demand to a return fuel line for an internal combustion engine.